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<H1>IBM Visualization Data Explorer Programmer&#39;s Reference</H1>
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<H2><A NAME="HDRPHOS" HREF="progu072.htm#PToC_157">15.3 Path Operations</A></H2>
<A NAME="IDX1211"></A>
<A NAME="IDX1212"></A>
<P>
The following operations produce a geometric Object from
a path.
In addition to the functions noted here, the Render module is capable
of directly rendering a path as a series of one-pixel
lines.
A path is a Field with 1-dimensional regular connections.
A path can be created by, for example:
<PRE>
    f = DXNewField();
    DXSetComponentValue(f, "positions", ...);
    DXSetConnections(f, "lines", DXMakeGridConnections(1, n));
    DXEndField(f);
</PRE>
where <TT><STRONG>n</STRONG></TT> is the number of points.
<P>
Both of the operations listed here use "normals" and "tangent"
components if they are present; otherwise, they compute
approximations to the normals and tangents,
as follows:
the tangent is the first derivative of the path; the normal is
perpendicular to the tangent and lies in the plane formed
by the tangent and the second derivative of the path.
In each case, appropriate normals are associated with the
result for shading.
<TABLE CELLPADDING="3">
<TR VALIGN="TOP"><TD><P><TT><STRONG>Object DXRibbon()</STRONG></TT>
</TD><TD><P>Produces a ribbon of the given width from a path or group of paths.
<A NAME="IDX1213"></A>
<A NAME="IDX1214"></A>
See  <A HREF="progu296.htm#HDRDXRIB">DXRibbon</A>.
</TD></TR><TR VALIGN="TOP"><TD><P><TT><STRONG>Object DXTube()</STRONG></TT>
</TD><TD><P>Produces a tube of a given diameter from a path or group of paths.
<A NAME="IDX1215"></A>
<A NAME="IDX1216"></A>
See  <A HREF="progu336.htm#HDRDXTBE">DXTube</A>.
</TD></TR></TABLE>
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